Animating is a matter of providing appropriate coords. You know the direction, increase a scalar and you’re good. Opacity can be animated as well.
Widgets can use splines these days, too - considering how the entire visual scripting is a bunch of animated wires… it’s high time they did, right?
Also:
https://www.unrealengine.com/marketplace/en-US/product/niagara-ui-renderer?sessionInvalidated=true